Means for latching armatures of electromagnetic devices



Oct. 23, 1962 J, ow ETAL 3,060,354

MEANS FOR LATCHING ARMATURES OF ELECTROMAGNETIC DEVICES 2 Sheets-Sheet 1 Filed Aug. 11, 1960 FIG. I.

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MEANS FOR LATCHING ARMATURES OF ELECTROMAGNETIC DEVICES INVENTORS. J.Y. HOWARD AND ESCRAIG THE|R ATTORNEY United States Patent 3,060,354 Patented Oct. 23., 1962 3,060,354 MEANS FOR LATCHING ARMATURES F ELECTROMAGNETIC DEVICES James Y. Howard, Spencerport, and Frank S. Craig, Chili, N.Y., assiguors to General Railway Signal Company, Rochester, NY.

Filed Aug. 11, 1960, Ser. No. 48,983 2 Claims. (Cl. 317187) This invention relates to electromagnetic devices having t-ractive type armatures, and more particularly relates to a means for latching the armatures in a biased deenergized position.

Although tractive type electromagnetic devices are commonly used to operate relay contacts, indicators, light signals and the like, the latching means of the present invention has particular utility when used in connection with the operation of a multiple indication light signal which employs two tractive type armatures arranged to be energized one at a time.

Multiple indication light signals of this particular type are used to regulate trafiic on railroads, and in general comprise a three color position spectacle of the vane type which is constructed to be operated by the armatures in a manner whereby the color glass roundels of the spectacle vane may be positioned one at a time in a fixed light beam in accordance with the different operated positions of the armatures.

More specifically, in operation the spectacle vane is normally positioned in its center position when both armatures are deenergized, due to the gravity bias of the armatures. Such center position is chosen as the danger or red indication position of the signal in accordance with regular signaling practice which specifies that the danger position shall be the tail-safe position. energization of one electromagnetic device will attract and pick up its armature and cause the spectacle vane to be rotated to a caution or yellow indication position. Likewise, the energization of the other electromagnetic device will attract and pick up its armature and cause the spectacle vane to be rotated to a clear or green indication position.

The energizing circuit is such that only one electromagnetic device may be energized at any given time and the spectacle vane always returns to its center position upon deenergization of the active electromagnetic device in accordance with the gravity biased movement of its armature to a dropped-away position against its back stop. Each armature also actuates contact fingers which cooperate with stationary contacts to indicate electrically the various positions of the armatures and the associaed spectacle vane.

In actual practice the signal mechanisms are usually mounted on high poles along the railroad right of way and as a consequence they are subject to severe vibrations due to train movements. Also, either high winds or a signal maintainer climbing the signal pole can cause the pole to sway and slightly tilt the signal mechanism with respect to the vertical axis of the spectacle vane. Such vibration and tilting of the signal mechanism has been known to cause momentary false signal indications due to the forced movement of the spectacle vane which would lift the armature off their back stops, thus making and breaking the armature mounted contacts and actually displaying flashes of the yellow or green indicators when traflic conditions called for a red indication to be displayed.

The present invention provides a means to mechanically latch the armatures of the electromagnetic devices and their associated spectacle vane in the red indicating positions and hold the mechanisms in such position until one or the other of the electromagnetic devices is ac- The a 2 tually energized. Upon the energization of one electromagnetic device its armature is first magnetically unlatched and then permitted to be attracted to its pickedup position. As previously mentioned, the energizing circuit is such that only one armature can be picked up at any given time.

The electromagnetic devices which operate the spectacle vane may be of any well known type such as commonly used in tractive type relays and each primarily comprises a double core structure in whicheach core is provided with a coil winding and an enlarged pole piece. A pivoted armature is mounted in magnetic relationship with the pole pieces and is normally positioned with a sizable airgap existing between the flat side of the armature and the flat ends of the pole pieces. When the coil windings are energized a flux path is set up through the core structure and across the airgap to the armature, thus attracting the armature to the pole pieces. This action causes a movement of the free end of the pivoted armature and such movement is utilized to operate the spectacle vane and contact fingers of the light signal.

The latching means of the present invention is also provided with a movable armature associated with the same pole pieces. It is spring biased away from the pole pieces and is magnetically attracted to the pole pieces of the electromagnetic device when it is energized to attract the main armature.

In general, the armature of this latching means comprise a piece of iron which is attached to a nonmagnetic resilient fiat spring arm which is fixedly mounted at one end and has its other end free. The flat spring arm is positioned so that the armature iron lies in magnetic relationship with the sides of the two pole pieces of the electromagnetic device with the usual airgap therebetween. The free end of the flat spring arm is provided with a bumper block which cooperates with a bumper piece located on the free end of the main armature of the electromagnetic device. The relationship is such that the bumper block of the latching armature intercepts the bumper piece of the operating armature when their respective electromagnetic devices are in their deenergized positions.

Such deenergized position is considered the normal position if the electromagnetic device and the spring bias of the latching arm away from the pole pieces positions its bumper block in the path of the armature bumper piece, thus preventing any upward movement of the armature and its associated spectacle vane when in such normal deenergized position. However, upon energization of the coils of any one particular electromagnetic device, the initial flux created in the core structure will immediately attract the relatively light weight latching armature to the sides of the pole pieces, thus moving the latching arm and its associated bumper block out of the path of the main armature bumper piece. As the flux in the core structure builds up, the main armature (which is relatively heavy) is then attracted to the bottom of the pole pieces and a normal operation of the spectacle vane occurs.

Another advantage of the latching means of the present invention lies in the fact that the armature of the other electromagnetic device remains in its latched position during the operation of the first mentioned electro magnetic device, thus preventing any so called overrun of the spectacle vane upon its return by the first mentioned armature to its deenergized position. As the one armature falls away to its down position due to gravity and rotates the spectacle vane towards its center position, a certain amount of momentum is built up which normally tends to rotate the spectacle vane beyond its center position, thus tending to pick up the other armature to the extent that its contacts may under certain 3 adverse conditions be operated and the spectacle may even display a false color indication. However, with the other armature latched in its down deenergized position, such an overrun movement is prevented.

Other objects, purposes and characteristic features of the present invention and the operation thereof will be more apparent from the following detailed description when considered in connection with the accompanying drawings in which:

FIG. 1 is a front view of a signal operating mechanism incorporating the latching means of the present invention and is shown somewhat diagrammatically to better illustrate the electromagnetic structures and their associated spectacle vane in their normal deenergized positions;

FIG. 2 is a plan view partly in section and partly broken away of the apparatus shown in FIG. 1 substantially as taken on the line 2-2 of FIG. 1 as viewed in the direction of the arrows, and shows the latching means of the present invention in its normal spring biased latching position;

FIG. 3 is a side view partly in section and partly broken away as part of the apparatus shown in FIGS. 1 and 2 substantially as taken on the line 33 of FIG. 2 as viewed in the direction of the arrows;

FIG. 4 is a partial view similar to FIG. 2 except that it shows only one of the electromagnetic structures and it is shown in its operated energized position; and

FIG. 5 is a partial view similar to FIG. 3 except that it shows the electromagnetic structure in its operated energized position.

The present invention is considered to be an improvement in light signal structure over that structure shown and described in the Hewes Patent No. 2,750,577, dated June 12, 1956. Since the present invention relates to the provision of an armature latching means for each electromagnetic device of such a light signal to effect the purposes generally described above without certain snulbbing means disclosed in such patent, it is believed to be necessary to only show in the disclosure of the present invention those parts more particularly relating to the improvements. If additional details of such a signal are desired, reference may be made to such prior Hewes Patent No. 2,750,577.

Referring now more particularly to FIGS. 1, 2 and 3 of the drawings, there has been shown a spectacle arm 11 to which is suitably attached at its upper end a spectacle 12. The spectacle 12 is provided with the usual color glasses designated Y, R and G to indicate the colors used, namely, yellow, red and green. These color glasses are suitably spaced and mounted to be positioned one at a time in front of a light beam source 13 when the spectacle arm 11 is rotated to a particular one of its three positions, as explained hereinafter. The spectacle arm 11 is of necessity light in weight and is preferably channel shaped in cross section for strength and rigidity.

Attached to the bottom end of the spectacle arm 11 by rivets or the like is a U-shaped bracket 14 which provides a :bearing for the pivot pins '15 and 15A on which the spectacle arm 11 is pivotally supported. These pivot pins 15 and 15A are mounted in the free ends of the respective armatures 16 and 16A of the two electromagnetic operating devices and are positioned so that they extend into their respective spectacle arm bearings from opposite directions. The two electromagnetic structures are mounted on the base plate 17 of the signal mechanism in side by side positions with the spectacle arm positioned therebetween, as more clearly shown in FIG. 2. As these two electromagnetic devices are exactly the same in structure, a brief description of one should suflice, the like parts having been given like reference numbers with a distinctive exponent A added thereto.

Each electromagnetic device is provided with an iron core structure comprising two core pieces 18 and 19 having enlarged pole pieces 20 and 21 respectively on one end thereof. The core pieces 18 and 19 are bridged at their other ends by the usual back strap 22 (illustrated by a dot and dash line) and are provided with the usual coil windings 23 and 24 respectively. The structure is mounted on and fastened to the base plate 17 by means of rivets or the like 25. Each core structure has its flat armature 16 positioned in magnetic relationship therewith. This armature lies directly under the pole pieces 20 and 21 and is suitably pivoted at one end to the base plate 17 by means of trunnion pins 26. Thus, the free end of the armature 16 is gravity biased to a downward position, which position is limited by an adjustable stop screw 27 which is also mounted in the base plate 17.

As previously mentioned, the armature 16 is provided at its free end with a pivot pin 15 which extends from its inner side surface and is journaled in the bracket portion 14 of the spectacle arm 11, as clearly shown in cross section in FIG. 2. Likewise, the armature 16A is provided at its free end with a pivot pin 15A which extends from its inner side surface and is journaled in the bracket portion 14 of the spectacle arm. 11. Thus, the spectacle arm 11 is fully supported on the pivot pins 15 and 15A with the weight of spectacle arm 11 and the armatures 16 and 16A resting on the stop screws 27 and 27A when the signal mechanism as a whole is in its normal deenergized center position with the red indication displayed. The spectacle arm 11 may be initially adjustably rotated to an exact center position with respect to the light beam source 13 by means of adjustment of the stop screws 27 and 27A.

Also attached to each of the armatures 16 and 16A is a contact operating means and two position contacts which have been illustrated herein diagrammatically. As shown in FIG. 1, the operating means has been illustrated as a dash line 28 and the contact fingers 29 and 30 are operated between front and back contact positions by the movement of the armature 16. These contacts usually control signal repeater circuits and the like.

With respect to the description of the apparatus as given so far which pertains to a standard signal mechanism, it can be seen and understood that the spectacle arm has two separate and distinct pivot points. For example, when it is desired to display the green indication, the coil windings 23 and 24 are energized causing a flow of flux through the core structure comprising the two cores 18 and 19, the two pole pieces 20 and 21, the back strap 22 and the armature 16. When the flux strength is built up to a suflicient capacity, the armature 16 will be attracted to the pole pieces 20 and 21, thus causing an upward movement of the free end of the armature 16 and its associated pivot pin 15. This action causes the spectacle arm 11 to rotate counterclockwise on the pivot pin 15A and place the green color glass G in the path of the light source 13. Upon deenergization of the coil windings 23 and 24, the gravity bias of the armature 16 and the spectacle arm will cause them to return to their normal positions with the armature 16 against its stop screw 27 and the spectacle color glass R in the path of the light source 13.

Similarly, when it is desired to display a yellow signal indication, the coil windings 23A and 24A (not shown) of the other electromagnetic device are energized, causing its armature 16A and associated pivot pin 15A to move upward. The spectacle arm 11 will now pivot on the pivot pin 15 and rotate clockwise so that the color glass Y will be positioned in the path of the light source 13. Here again, deenergization of the coil windings 23A and 24A will permit the spectacle arm 11 to return to its center normal position.

It is at this time of return of the spectacle arm 11 to its center position that so-called overrun movements of the spectacle arm 11 occur. This return movement is caused by the gravity bias of both the armature and the spectacle arm. As the spectacle arm 11 rotates, inertia is built up which causes it to move beyond the center position and momentarily display a yellow or green indication. As the spectacle arm 11 moves past the center position, the downward moving armature has come to a stop against its stop screw and its pivot pin then acts as a pivot for the spectacle arm 11, thus permitting the spectacle arm 11 to raise the opposite armature through its pivot pin. In so doing, the armature contacts are also operated, causing false circuit indications. Also, as previously mentioned, severe jars and vibrations or tilting of the signal mechanisms may cause the armatures to move upward away from their stop screws, thus causing un- Wanted movements of both the armature contacts and the spectacle arm.

Referring now to the latching means of the present invention, its purpose is to prevent unwanted movements of both the armatures and the spectacle arm as just described. Here again, the latching means for both the armatures 16 and 16A are alike in structure and only one will be described in detail, like reference numbers having been used with a distinctive exponent A added thereto.

Each latching means of the present invention comprises in general an auxiliary armature which is positioned in magnetic relationship to the pole pieces of the existing electromagnetic structures. The armature comprises a piece of iron 31 which is attached to a resilient nonmagnetic finger 32 by rivets or the like. The finger 32 is fastened at one end to a rigid support 33 which in turn is mounted on the side of the base plate 17 by means of screws 34. Attached to the free inwardly turned end of the finger 32 is a block 35 of hard material such as molded insulation or the like. In assembly, the armature piece 31 lies substantially parallel to the sides of the pole pieces 20 and 21, with a slight airgap therebetween and the resilient finger 32 and its associated armature piece 31 are spring biased to an outward unattracted position. The block 35 lies between the base plate 17 and the free end of the main armature 16 and acts as a bumper block to normally restrict the upward movement of the main armature 16.

This main armature 16 is also provided with a bumper 36 which is in the form of a hook shaped metallic bracket the end of which normally engages a notch 37 formed in the bumper block 35, as shown in FIG. 3. The main purpose of the notch 37 is to limit the outward biased movement of the finger 32 so that a fixed airgap is maintained between the auxiliary armature 31 to the pole pieces 20 and 21. In this normal position of the latch ing means, it can be seen that any tendency of the free end of the armature 16 to move upward would be prevented as the bumper piece 36 of the armature 16 is hearing against the bumper block 35 of the latching armature, which block 35 in turn would bear against the bottom of the base plate 17 if forced upward.

With reference now to the operation of the signal mechanism with the latching means of the present invention applied thereto, it can be seen that the bumper block 35 must first be moved out of the path of the bumper piece 36 before the main armature 16 can be picked up. With reference to the operating procedure previously described, the energization of the coil windings 23 and 24 will cause a flow of flux through their respective core structure, which flux strength must be built up to a capacity sufficient to attract the heavy armature 16. However, as the auxiliary armature 31 of the latching device is small in size and comparatively light in weight, it will be almost immediately attracted to the sides of the pole pieces 20 and 21. This action moves the resilient finger 32 and its associated bumper block 35 in a horizontal direction and out of the path of the upward movement of the bumper piece 36 and its associated armature 16. Thus, the armature 16 may then be attracted up- 6 ward to its closed position in a normal manner, as shown in FIGS. 4 and 5.

Upon deenergization of the coil windings 23 and 24, the armature 16 will drop away to its down position against its stop screw 27 due to its gravity bias. In this down position, the bumper piece 36 of the armature 16 is again below the plane of the bumper block 35 so that the spring bias of the armature supporting finger 32 will cause the bumper block 35 to move over the bumper piece 36 to a position where the tip end of the bumper piece 36 will again engage the notched portion 37 of the bumper block 35. Thus, the armature 16 is again latched in its down position until such time as the coil windings 23 and 24 are again energized.

As previously mentioned, the signal operating mechanism is such that only one electromagnetic device is energized at any given time. As a consequence, one armature is always latched in its deenergized down position while the other armature is being operated. With reference again to the operation of the armature 16 as described above, it can now be seen that as the armature 16 and spectacle arm 11 return to their normal positions, any so called overrun movement of the spectacle arm 11 past its center position is prevented. This is true because the spectacle arm 11 in order to move beyond its center position, would have to pick up the armature 16A due to its connection to the armature 16A by means of its pivot pin 15A. As the armature 16A is at this time latched in its down position, such an upward movement of the armature 16A and an overrun movement of the spectacle arm 11 cannot occur.

Also, as both armatures 16 and 16A are latched in their down deenergized positions, it can be seen that any abnormal vibrations or tilting of the signal mechanism will not in any way effect a movement of the spectacle arm 11 or the armature contacts 29, 29A, 30 and 30A while the spectacle 12 is in its center position and displaying a red or danger indication.

Although the latching means of the present invention has been shown and described as applied to a three position light signal mechanism having two electromagnetic devices included in its operating mechanism to better illustrate its versatility, it should be undersood and also be quite obvious that such a type of latching means could be used to latch the armature of any of the well known type of relay devices employing a tractive type armature. When used with such a relay, the purpose would be to prevent false operation of the relay contacts due to any movement of the relay armature caused by severe vibrations and the like such as encountered, for example, in railway signaling practice.

Having shown and described one form which the latching means of the present invention can assume .and having described and illustrated its use and various utilities in connection with the operation of one of the more complicated railway signal mechanisms, it should be understood that modifications could be made therein and other uses could be made thereof, all without departing from the spirit of the invention within the scope of the appending claims.

What we claim is:

1. In an electromagnetic device having an electroresponsive device and an armature supported at one end by a fixed pivot and having its other end free to move about such pivot in response to the energization of said electroresponsive device the combination comprising, an arm fixedly attached to said armature, a spring with one end thereof fixedly connected to said electromagnetic device, said spring being outwardly biased from said electroresponsive device with a magnetic bar mounted thereon for being influenced by said electroresponsive device and a bumper block fixedly connected to said spring effective to engage said arm of said armature whereby said armature is continually restricted in a yieldable manner from moving toward said electroresponsive device as long as said magnetic metal mounted on said spring is not first influenced by said electroresponsive device.

2. In an electro-magnetic device in accordance with claim 1 wherein said bumper block fixedly connected to said spring is slotted to engage said arm of said armature in such manner that said magnetic bar mounted on said spring is continually retained in position to be influenced by said electroresponsive device.

References Cited in the file of this patent UNITED STATES PATENTS 

